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G. W. JOHNSTON 8: P. BROWN. HIGH PRESSURE ALARM FORSTEAM BOILERS.

Patented Mar. 18, 1884 BY ATTORNEYS.

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HIGH-PRESSURE ALARM FOR STEAM-BOlLERS SPECIFICATION forming part ofLetters Patent No. 295,456, dated March 18, 1884.

Application filed July 30, 1983. (110 model.)

To rtZZ whom it may concern:

Be it known that we, Ormnnns W. Jonas- TON, of Germantown, in the cityand county of Philadelphia and State of Pennsylvania, and PATRICK Bnown,of Chestnut Hill, in the city, county, and Stateaforesaid, have inventedcertain new and useful Improvements in High-Pressure Alarms forSteam-Boilers, of which the following is a full, clear, and exactdescription.

This invention consists in an improved safe ty-valve and alarm, or whatmay be more correctly termed an improved high-pressure alarm, forsteam-boilers, whereby the weightlifting part or device exposed to theaction of the steam is kept in continuous or frequent V motion by thevarying pressure of the steam in the boiler above a given limit,substantially as hereinafter described, and whereby the danger which sofrequently arises from the sticking of the ordinary safety-valve isavoided.

Reference is to be had to the accompanying drawings, forming a part ofthis specification, in which similar letters of reference indicatecorresponding parts in all the figures.

Figure 1 represents a partly sectional side view of our improvedapparatus or alarm, as

applied to a steam-boiler. Fig. 2 is a trans verse vertical section ofthe same on the line r :r in Fig. 1. Fig. 3 is a horizontal section, inpart, on the line 3,1 1 in Fig. 1.

A is a pipe secured on or in the top of a steam-boiler, B, or otherwiseconnecting with the steam-space of the boiler, and which may be fittedwith a cook or valve, 1), for shutting off connection of the apparatuswith the boiler when required. The outer or upper end of thispipeconnection A screws into or connects with the lower end of astuffing-box, B, which is fitted with a suitable packing, a, and glandd. Arranged to pass down within thepacking of this stuffing-box B is aplunger, G, which may be of tubular construction, closed on top byascrew-cap, e, and which, when fully down, may rest upon the bottom ofthe stoning-box or upper end of the pipe A. Said plunger may have itsbody formed of a piece of pipe of the same diameter as the pipe A, orsaid plunger might be made solid.

Dis a rod fitted to screw at its lower end into the top or cap e of theplunger G, and arranged to pass upward through a weight, E,

l which rests on top of the cap, and is slipped over said rod. This rodprojects slightly above the top of the weight E, for a purpose that willbe hereinafter described; or the weight itself may be suitablyconstructed to produce directly the same result.

G is a frame consisting of front and rear upright arms arranged toproject above the weight E, on opposite sides of it, and secured belowin any convenient way to the pipe A or stuffing-box B'as, for instance,by screwing a lower part, which connects the two arms,

onto the upper portion of said pipe.

H is alcver having arms of unequal length, and arranged above the weightE, said lever being pivoted at f to the upper portion of the rear arm ofthe frame G, and passing through a slot, g, in the front arm thereof, ofsufficient depth to allow of the lever moving up and down therein whenthe alarm. is in action, but restricting the portion of the leverpassing through it from being lifted above a certain height, to preventthe plunger 0 from passing out of its stuffing-box B. This lever carriesa weight, I, on its longer arm, and its shorter arm connects with orrests on a short valve lever or arm, 71., of a steam-whistle, J, so thatwhen the longer arm of the lever H is lifted its shorter arm acts uponthe arm h to open the whistle for the purpose of sounding the alarm.Said whistle may be fitted with a cook or valve, 23, for shutting offcommunication with the boiler when required.

K is a spring arranged beneath the longer arm of the lever H, for theweight E orupper end of the rod D to act against and compress when saidweight is raised 5 or said spring might be arranged on top of the weightE to have the same effect. The weights E I and spring K are allproportioned to resistcertain pressures which are arbitrary.

The operation is as follows: The valves I) i being opened, supposing itis desired to carry eighty (80) pounds of steam in the boiler, and thatit might be considered dangerous to subject it to ninety (90) poundspressure on the square inch, then the weight E, plus the friction of theplunger Gin the stuffing-box, should exert a dead-weight of eighty (80)pounds. This will just counterbalance the safe or desiredworking-pressure of the steam in the boiler, and there will be notendency to lift said weight and plunger from their lowermost positionsshown in the drawings. Upon any increase of pressure, however, of thesteam in the boiler above eighty (80) pounds, the plunger O and weight Ewill be raised, and said weight or upper end of the rod D will pressagainst the spring K and cause it to yield, and as the steam-pressurestill further increases will continue to so compress the spring untilthe steam reaches ninety (90) pounds pressure, when the spring will havereached its utmost tension, and the long arm of the beam or lever H willthen be raised and its short arm caused to act upon the lever h, to openthe valve of the whistle J and sound the alarm. Upon thesteam loweringagain in the boiler to the desired eighty (80) pounds pressure, theseveral working parts of the apparatus will resume their normalpositions, and any fluctuations of pressure between eighty (S0) andninety (90) pounds, supposing these to be the safety and danger limits,will keep the plungerG in constant or corresponding up-and-down mot-ionwithout blowing ott' or wasting steam, and so will avoid all liabilityof the plunger to stick, as ordinary safety-valves, when allowed tostand closed for any length of time, endangering explosion of theboiler, are liable to do.

Instead of the steam-whistle. any other alarm device might be used, orthe same might be in the form ofa mere indicator, and springs might beused as equivalents for the weights E and I. Various other changes maybe made, which in no wise alter the distinguishing character orprinciple of the invention. Thus, a piston, which would be equivalent ofthe plunger 0, may be used instead of it. The weight-rod D may beextended upward to passthrough an oblong guide-hole in the beam or leverH, for the purpose of steadying the weight E and keeping the plunger orpiston in line with the tube or stuffing-box in which it works, and sorelieving the packing of strain It is generally proposed to use theapparatus in connection with a blowott'safety-valve; but in this case itshould be so weighted that it will operate to lift its direct weight Ewhen the pressure is several points below that which is required toraise the blow-off sai'etywalve, v

and will raise the weighted beam or lever H, to give the alarm, when thepressure slightly exceeds that at which said safety-valve shouldoperate, so that in case of the safety-valve sticking the alarm will begiven.

In some cases the spring K might be dispensed with and the weighted rodD, after being raised a given distance, be made to act directly, bymeans of side ears or otherwise, upon the loaded beam or lever H, to indue course lift said lever, should the pressure in the boiler besutficiently increased.

. Having ,thus described our invention, we claim as new and desire tosecure by Letters Patent 1. A highpressure alarm apparatus forsteanrboilers, provided with a loaded steamplunger and with asupplementary resistance device arranged for actuation by said plungerto give or sound the alarm, whereby the pluir ger is kept in motion byfluctuations in pressure of the steam in the boiler, essentially asspecified.

2. In higlrpressure alarms for steam-boih ers, the combination of theplunger 0 and stuffing-box B, for connection with a pipe leading fromthe steam-space of the boiler, the weight E, the superposed weightedlever H, and an alarm device operated by said lever H, substantially asspecified.

3. In high-pressure alarms for steam-boilers, the combination of thespring K, with the weighted lever H, and an alarm device operated bysaid lever, the weight E, the plunger G, and the. stuttingbox B, forconnection with the steam-space ot' the boiler, essentially as and forthe purposes herein set forth.

4. The combination of the steam pipe or connection A, the stuffing-boxB, the plunger G, the rod D, the weight E, fitted to slip over said rod,the frame G, the weighted lever H, the spring K, and the steam-whistleJ, for operation by the lever I-I, substantially as shown and described.

CHARLES WV. JOHNSTON. PATRICK BBOXVN. WVitnesses:

Gno. B. MoBAUM, llIIOI-IAEL MONAMEE.

